#include<bits/stdc++.h>


using namespace std;
int ini = []{
	cout << "hello lambda" << endl;
	return 0;
}();

int main(){
	vector<int> a{1,0,0,1};
	int sum = 0;
	for(int i = 0; i < a.size(); i++){
		sum = sum * 2 + a[i];
	} 
	cout << sum << endl;
	return 0;
} 
